The device contains several
multicontroller Inter-Integrated Circuit (I2C) controllers. Each I2C controller was
designed to be compliant to the Philips I2C-bus™ specification version 2.1. However,
the device IO Buffers are not fully compliant to the I2C electrical
specification. Some I2C instances use the LVCMOS Buffer Type, while other
instances use the I2S OD FS Buffer type. See the Pin Attributes table to
determine the IO Buffer Type used for each I2C instance on this device. The
I2C speeds supported and exceptions are described per IO Buffer
Type below:
- I2C instances that use the
LVCMOS buffer type
- Speeds:
- Standard-mode
(up to 100 Kbits/s)
- Fast-mode (up
to 400 Kbits/s)
- Exceptions:
- The IOs
associated with these ports are not compliant to the fall
time requirements defined in the I2C specification because
they are implemented with higher performance LVCMOS
push-pull IOs that were designed to support other signal
functions that could not be implemented with I2C compatible
IOs. The LVCMOS IOs being used on these ports are connected
such they emulate open-drain outputs. This emulation is
achieved by forcing a constant low output and disabling the
output buffer to enter the Hi-Z state.
- The I2C
specification defines a maximum input voltage VIH
of (VDDmax + 0.5 V), which exceeds the
absolute maximum ratings for the device IOs. The system must
be designed to ensure the I2C signals never exceed the
limits defined in the Absolute Maximum
Ratings section of
this data sheet.
- I2C instances that use the
I2C OD FS buffer type
- Speeds:
- Standard-mode
(up to 100 Kbits/s)
- Fast-mode (up
to 400 Kbits/s)
- Hs-mode (up
to 3.4 Mbit/s)
- Exceptions:
- The IOs
associated with these ports were not design to support
Hs-mode while operating at 3.3 V. So Hs-mode is limited to
1.8-V operation.
- The rise and
fall times of the I2C signals connected to these ports must
not exceed a slew rate of 0.8 V/ns (or 8E+7 V/s). This limit
is more restrictive than the minimum fall time limits
defined in the I2C specification. Therefore, it may be
necessary to add additional capacitance to the I2C signals
to slow the rise and fall times such that they do not exceed
a slew rate of 0.8 V/ns.
- The I2C
specification defines a maximum input voltage VIH
of (VDDmax + 0.5 V), which exceeds the
absolute maximum ratings for the device IOs. The system must
be designed to ensure the I2C signals never exceed the
limits defined in the Absolute Maximum
Ratings section of
this data sheet.
Refer to the Philips I2C-bus
specification version 2.1 for timing details.
For more details about features and additional description information on the device
Inter-Integrated Circuit, see the corresponding subsections within Section 6.3 and Detailed Description.